Barrel for portable firearms and cannon with deepened grooves.



No. 868,938. PATENTED OCT. 22. 1907.

G. PUFF.

BARREL FOR PORTABLE FIREARMS AND CANNON WITH DEEPBNED GROOVES.APPLIOATION TILED JULY 25. 1907.

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UNITED STATES PATENT OFFICE.

CARL PUFF, OF SPANDAU, GERMANY.

BARREL FOR PORTABLE FIREARMS AND CANNON WITH DEEPENED GROOVES.

Specification of Letters Patent.

?atented Oct. 22, 1907.

To all whom it may concern:

Be it known that I, CARL Pm, a subject oi the German Emperbr, and aresident of Spandau, Germany, have invented certain new and usefulImprovements in Barrels for Portable Firearms and Cannons with DeepenedGrooves, of which the following is a specification.

The invention relates to the rifiing of firearm barrels designed to fireprojectiles, which, in addition to the usual guiding means, are providedwith special driving plates or disks, or the like, of increaseddiameter, which offer a large pressure area and a smaller sectionalcharge of the projectile, especially at the beginning of the developmentof the gases.

Such projectiles have usually been fired until now by means ofstrongly-conical barrels. It follows that the driving disks, which havea greatly larger diameter than the projectile, must be very long if theprojectile is to be properly guided.

According to the present invention, the barrel is cylindrically-bored,while the rifiing grooves are made deeper than is usual and necessaryfor imparting the desired torque to the projectile, this deepening ofthe grooves being found in the region of the breech and diminishingtoward the muzzle, where the grooves may be of normal depth. I desire toemphasize that the essence and underlying principle of my invention isthe deepening of the riding grooves, as contradistinguished from makingthese grooves shallower than normally. It will be understood that, forany given caliber, a certain depth of groove is absolutely necessary toproduce the proper effect upon the projectile,-that is, to cause it torotate at the proper speed.

I am aware that, heretofore, it has been proposed to cause rifiinggrooves, normal at the breech, to become shallower toward the muzzle,where they are necessarily of a depth less than is requisite for givingthe proper twist to the projectile. It will be obvious that all suchconstructions are entirely foreign to my invention, since they lackentirely the essence thereof, namely the deepening of the groovcs,-infact, they constitute the very antithesis of my construction,shallow'ing instead of deepening the grooves.

In my construction, the deepened portions of the grooves are filled bythe driving disk or collar on the projectile, but not by the body of theprojectile proper.

The guiding surface of the projectile body enters the grooves only tothe usual or normal depth; and the driving disks or collars arecompressed as the projectile advances and the grooves shallow to normaldepth toward the muzzle. Or the driving disks may be stripped off fromthe projectile by suitable means located adjacent the muzzle. The objectof deepening the grooves toward the breech and causing such deepenedportions to be filled by the driving collars is to afford an enlargedpressure area on the projectile, whereby-the gas pressure isconsiderably reduced, or, if the gas pressure remains the same, thespeed of the projectileisincreased.

, The essential features of the invention, and certain of the possibleembodiments thereof, will be readily comprehended by reference to thedrawings forming a part of this application and in which:

Figure 1 is a diagrammatical longitudinal section through a barrel, inwhich the grooves shallow from abnormal depth at the breech to normaldepth at the muzzle, showing a projectile with its driving disk; Fig. 2is a cross-section taken through Fig. 1 just in advance of thetransition cone; Fig. 3 is a longitudinal section through a. barrel,showing a different form of projectile which may be used; Fig. 4 is across-section through a different form of barrel; Fig. 5 is a 1ongitudin-a1 section of a form of barrel in which the driving disk is strippedoff the projectile at the muzzle; Fig. 6 is a fragmentary longitudinalsection through a barrel, showing a different form of projectile whichmay be employed; and Figs. 7-9 show other forms of projectiles.

In Fig. 1 of the drawings, 11-!) is the bore proper of the barrel, orthe diameter between lands, 0-11 the normal depth of the grooves, ef thedeepened part of the grooves, extending through the length g-h, 1Ik thetransition cone extending from the rear endsof the grooves to thesurfaces of the lands, 1 the body of the projectile, and 2 the drivingdisk or collar thereof. The length 9-7 of the deepened part of thegrooves may be chosen at will. In the diagrammatical illustration, thediameter of the collar 2, as well as the deepening of the grooves, hasbeen somewhat exaggerated. The form and cross-section of the lands maybe quite arbitrary, for instance they may be narrower at the rear thantoward the muzzle.

In Fig. 3 is shown a projectile 3,11avinga free driving disk 4.

Fig. 4 shows a form of barrel in which the ribs m left between groovescorrespond to the diameter of the driving disk, while the narrow ribs nare of the usual depth and cut into the guiding surface of theprojectile.

In the form of barrel shown in Fig. 5, the grooves not only shallow fromthe rear until they have reached normal depth, but are progressivelymade still shallower, until they vanish toward the muzzle. When thedriving disk on the projectile reaches this region, it is stripped off,and may be thrown out through openings 6,

Fig. 6 shows a; projectile having a driving disk 7 which is in theformof a, cup.

Figs. 7 8 and 9 show projectiles with other forms of driving disks.

Having now fully described my invention; what I claim as new is:

A bnrrel for portable firearms and guns adapted to fire projectilesprovided with enlarged driving disks, having eeeese rifiing grooves ofgreater than normal depth at the rear and shallowing to normal depth andfinally disappearing 10 at the muzzle, and having also a lateral openingadjacent the muzzle for the discharge of the driving disk.

In testimony whereof I have hereunto-set my hand in presence of twowitnesses.

CARL PUFF. Witnesses I'IENRY HAsPEn, WOLDEMAR HAUPT.

